/*
 * Copyright 2015 Austin Keener, Michael Ritter, Florian Spieß, and the JDA contributors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package net.dv8tion.jda.internal.handle;

import net.dv8tion.jda.api.entities.Guild;
import net.dv8tion.jda.api.entities.Message;
import net.dv8tion.jda.api.entities.MessageType;
import net.dv8tion.jda.api.entities.channel.ChannelType;
import net.dv8tion.jda.api.entities.channel.middleman.GuildChannel;
import net.dv8tion.jda.api.events.message.MessageUpdateEvent;
import net.dv8tion.jda.api.utils.data.DataObject;
import net.dv8tion.jda.internal.JDAImpl;
import net.dv8tion.jda.internal.entities.EntityBuilder;
import net.dv8tion.jda.internal.requests.WebSocketClient;

public class MessageUpdateHandler extends SocketHandler {

    public MessageUpdateHandler(JDAImpl api) {
        super(api);
    }

    @Override
    protected Long handleInternally(DataObject content) {
        Guild guild = null;
        if (!content.isNull("guild_id")) {
            long guildId = content.getLong("guild_id");
            if (getJDA().getGuildSetupController().isLocked(guildId)) {
                return guildId;
            }
            guild = api.getGuildById(guildId);
            if (guild == null) {
                api.getEventCache().cache(EventCache.Type.GUILD, guildId, responseNumber, allContent, this::handle);
                EventCache.LOG.debug("Received message for a guild that JDA does not currently have cached");
                return null;
            }
        }

        // Drop ephemeral messages since they are broken due to missing guild_id
        if ((content.getInt("flags", 0) & 64) != 0) {
            return null;
        }

        if (content.hasKey("author")) {
            if (content.hasKey("type")) {
                MessageType type = MessageType.fromId(content.getInt("type"));
                if (!type.isSystem()) {
                    return handleMessage(content, guild);
                }
                WebSocketClient.LOG.debug(
                        "JDA received a message update for an unexpected message type. Type: {} JSON: {}",
                        type,
                        content);
                return null;
            }
        }
        return null;
    }

    private Long handleMessage(DataObject content, Guild guild) {
        Message message;
        try {
            message = getJDA().getEntityBuilder().createMessageWithLookup(content, guild, true);
            if (!message.hasChannel()) {
                throw new IllegalArgumentException(EntityBuilder.MISSING_CHANNEL);
            }
        } catch (IllegalArgumentException e) {
            switch (e.getMessage()) {
                case EntityBuilder.MISSING_CHANNEL: {
                    long channelId = content.getUnsignedLong("channel_id");

                    // If discord adds message support for unexpected types in the future,
                    // drop the event instead of caching it
                    if (guild != null) {
                        GuildChannel actual = guild.getGuildChannelById(channelId);
                        if (actual != null) {
                            WebSocketClient.LOG.debug(
                                    "Dropping MESSAGE_UPDATE for unexpected channel of type {}", actual.getType());
                            return null;
                        }
                    }

                    getJDA().getEventCache()
                            .cache(EventCache.Type.CHANNEL, channelId, responseNumber, allContent, this::handle);
                    EventCache.LOG.debug(
                            "Received a message update for a channel that JDA does not currently have cached");
                    return null;
                }
                case EntityBuilder.MISSING_USER: {
                    long authorId = content.getObject("author").getLong("id");
                    getJDA().getEventCache()
                            .cache(EventCache.Type.USER, authorId, responseNumber, allContent, this::handle);
                    EventCache.LOG.debug(
                            "Received a message update for a user that JDA does not currently have cached");
                    return null;
                }
                default:
                    throw e;
            }
        }

        if (message.getChannelType() == ChannelType.PRIVATE) {
            getJDA().usedPrivateChannel(message.getChannel().getIdLong());
        }

        getJDA().handleEvent(new MessageUpdateEvent(getJDA(), responseNumber, message));
        return null;
    }
}
